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The production of porous ceramics for biomedical applications is widely available in the Ceramics industry. In bioceramic applications, interconnected pores are pertinent to increase osteoconductivity and cell proliferation. However, an increase in pore size and the pore amount decrease the mechanical properties. For this reason, pore properties must be precisely controlled. In this study, the effect of a natural pore-forming agent, corn starch addition, and sintering conditions on mechanical properties and biocompatibility was investigated. During mixing, four different starch amounts (1, 3, 5, and 10 wt%) were added to pure beta-tricalcium phosphate (β-TCP) ceramic powders and pressed. Pressed pellets were sintered at 1000, 1100, 1200, and 1300 °C. A scanning electron microscope (SEM) is used to investigate microstructure, texture, pore size, and cell adhesion. The mechanical properties of the β-TCP ceramic parts were further characterized by measuring the density and compressive strength. Cytotoxicity tests were carried out with MTT assays. The optimum mechanical properties were obtained at 1100 °C sintered biocomposites. Although starch starts to burn around 410 °C and analytical results show no presence of starch after the sintering process, biocomposites initially containing 10% starch showed improved cell proliferation. However, a reduction of 59% in compressive strength and a 16% reduction in the density were also recorded. It was observed that 10 wt% starch addition increases cell proliferation by 10% in sintered β-TCP samples. Starch powder additions can be used to increase the cell viability of the material by facilitating the creation of pores, as a low-cost pore-forming agent for porous bone graft and non-load-bearing material in both orthopaedics and maxillofacial applications. [ABSTRACT FROM AUTHOR]

The aim of this study was to systematically investigate the apatite layer formation and protein adsorption on the bioceramics, trying to reveal their relationship and the mechanisms of the process. Four different materials, hydroxyapatite (HA), apatite/wollastonite bioactive glass ceramics (BGC), biphasic calcium phosphate (BCP), and nano-hydroxyapatite (nHA), were prepared to meet the specific tissue engineering scaffold requirements. The porous samples in four groups were immersed into simulated body fluid (SBF) solution, and the structural and morphological changes for different times (maximum of 14 days) were analyzed. Then, the effect of their structure and chemical composition on protein adsorption capacity was systematically compared. [ABSTRACT FROM AUTHOR]

Multifunctional porous biological hydroxyapatite (b-Hap) tablets prepared from fine bone powder (FBP) are predicted to be useful as a calcium supplement and at the same time as low-dose drug carriers. FBP was hydrothermally extracted, then mechanically compressed and sintered without using chemical additives to prepare the porous b-Hap tablets. The properties of FBP and b-Hap tablets were characterized by XRD, FTIR, SEM, mechanical, and porosity tests. Moreover, an aqueous drug solution of atenolol was used to evaluate release behavior from porous b-Hap tablets. The prepared FBP exhibited microstructures with grain sizes of about 50 to 100 μm while b-Hap tablets sintered at 800 °C exhibited high porosity (55%) and compression strength of 8.5 MPa. When the atenolol-loaded b-Hap tablets were immersed in the acidic medium, the release of atenolol from the tablets continued for 120 min with complete dissolution of the b-Hap tablets. These results indicate that the porous b-Hap tablets are promised as an economic calcium supplement and as low-dose drug carriers. [ABSTRACT FROM AUTHOR]

Apatitic tricalcium phosphate (ap-TCP) powders containing Mg were synthesized through wet chemical precipitation method from CaO and H 3 PO 4 , using MgO as the source of Mg substitution. The influence of small, close to bone-like amounts of Mg on the thermal stability and specific surface area (SSA) of as-synthesized ap-TCP powders was evaluated. The increase in Mg content up to 0.674±0.080 wt% promoted enlarging of SSA of the as-synthesized powders between 91.3 m 2 /g and 104.2 m 2 /g and the stabilization of the β-tricalcium phosphate (β-TCP) phase up to 1360 °C. The effect of Mg substitution on porosity and microstructure was investigated. Interconnected porous Mg-containing β-TCP scaffolds, with micro-, macroporous structures were developed by an in situ foaming of viscous mass of proper slurry prepared of the as-synthesized ap-TCP powders, using NH 4 HCO 3 as a foaming agent, and subsequent sintering at 1150 °C for 2 h. The self-dissolution behavior in vitro was evaluated through soaking of scaffolds in SBF. The release of Ca and Mg ions from the 3D micro-, macroporous β-TCP scaffolds containing various amounts of Mg was determined by a complexometric (EDTA) titration. The samples with increased Mg concentrations showed significantly enhanced Mg-release rate in comparison to the samples with lower Mg substitution level. [ABSTRACT FROM AUTHOR]

To improve the mechanical properties of a porous bioceramic without reducing its porosity, a new kind of porous hydroxyapatite (HA) bioceramic with in-situ grown HA whiskers was fabricated using a simple sintering method. CaSO4·2H2O was used as a pore-forming medium and also as a catalyst for the growth of in-situ HA whiskers. The bioceramic was analyzed by XRD, SEM and mechanical tests. In-situ grown HA whiskers were stratified on the cliffs of pores in the bioceramic. The compressive strength is as high as 21.7MPa with the porosity of about 26%. The results show that porous HA bioceramic can be improved in both compressive strength and porosity by the addition of CaSO4·2H2O. This novel HA bioceramic has a higher compressive strength without reducing its porosity in a certain weight ratio of CaSO4·2H2O, which depends on its two-step fracture pattern. This novel structure provides a new and promising reinforced pattern for porous materials. [ABSTRACT FROM AUTHOR]

Hydroxyapatite due to its good biocompatibility and similar chemical composition to the mineral part of bone has found various applications in tissue engineering. Porous hydroxyapatite has high surface area, which leads to excellent osteoconductivity and resorbability, providing fast bone ingrowth. In this study, highly porous body of nanostructure hydroxyapatite was successfully fabricated via gelcasting method. The pure phase of hydroxyapatite was confirmed by X-ray diffraction. The result of scanning electron microscopy analysis showed that the prepared scaffold has highly interconnected spherical pores with a size in the range 100-400 μm. The crystallite size of the hydroxyapatite scaffold was measured in the range 30-42 nm. The mean values of true (total) and apparent (interconnected) porosity were calculated in the range 84-91 and 70-78%, respectively. The maximum values of compressive strength and elastic modulus of the prepared scaffold were found to be about 1.5 MPa and 167 MPa, respectively, which were achieved after sintering at 1,000 °C for 4 h. Transmission electron microscopy analysis showed that the particle sizes are smaller than 80 nm. In vitro test showed good bioactivity of the prepared scaffold. The mentioned properties could make the hydroxyapatite scaffold a good candidate for tissue engineering applications, especially applications that did not need to stand any loading. [ABSTRACT FROM AUTHOR]

The aim of this research study is the preparation and characterization of graded glass-ceramic scaffolds that are able to mimic the structure of the natural bone tissue, formed by cortical and cancellous bone. The material chosen for the scaffolds preparation is a glass belonging to the system SiO2-P2O5-CaO-MgO-Na2O-K2O (CEL2). The glass was synthesized by a conventional melting-quenching route, ground, and sieved to obtain powders of specific size. The scaffolds were fabricated using different methods: polyethylene burn-off, sponge replication, a glazing-like technique, and combinations of these methods. The scaffolds were characterized through morphological observations, density measurements, volumetric shrinkage, mechanical tests, and in vitro bioactivity tests. The features of the scaffolds prepared using the different methods were compared in terms of morphological structure, pores content, and mechanical strength. The proposed scaffolds effectively mimic the cancellous/cortical bone system in terms of structure, porosity, and mechanical strength, and they exhibit a highly bioactive behavior. Therefore, these graded grafts have a great potential for biomedical applications and can be successfully proposed for the substitution of load-bearing bone portions. [ABSTRACT FROM AUTHOR]

This aim of this research was to develop a novel ceramic scaffold to evaluate the response of bone after ceramic implantation in New Zealand (NZ) rabbits. Ceramics were prepared by the polymer replication method and inserted into NZ rabbits. Macroporous scaffolds with interconnected round-shaped pores (0.5-1.5 mm = were prepared). The scaffold acted as a physical support where cells with osteoblastic capability were found to migrate, develop processes, and newly immature and mature bone tissue colonized on the surface (initially) and in the material's interior. The new ceramic induced about 62.18% ± 2.28% of new bone and almost complete degradation after six healing months. An elemental analysis showed that the gradual diffusion of Ca and Si ions from scaffolds into newly formed bone formed part of the biomaterial's resorption process. Histological and radiological studies demonstrated that this porous ceramic scaffold showed biocompatibility and excellent osteointegration and osteoinductive capacity, with no interposition of fibrous tissue between the implanted material and the hematopoietic bone marrow interphase, nor any immune response after six months of implantation. No histological changes were observed in the various organs studied (para-aortic lymph nodes, liver, kidney and lung) as a result of degradation products being released.